The present invention relates to using a mixture of a nonionic surfactant blend having an acidulated soybean soapstock component with a compatible herbicide to reduce an objectionable odor of the herbicide.
Liquid herbicides and dry, flowable herbicides are mixed with water in order to more economically apply the herbicides to crops. However, liquid and dry herbicides, even when mixed in water, have a limited capacity to pass through a leaf surface and then to translocate within a weed. A surfactant is added to the liquid and dry, flowable herbicides in order to help the herbicides enter the leaf surface of the weed. Once the herbicide enters a leaf surface of a weed, the herbicide can be translocated to an action site within the weed and can kill the weed.
Surfactants are also used to disperse herbicides in water. The surfactants include a lipophilic portion compatible with many herbicides and a hydrophilic portion compatible with water. Depending upon the herbicide, the surfactant used is suitably either ionic or nonionic.
Ionic surfactants include a molecular structure having a charge on the hydrophilic portion of the structure. Ionic surfactants having a positive charge are cationic surfactants. Ionic surfactants having a negative charge are anionic surfactants.
Nonionic surfactants include a molecular structure where the nature of chemical bonds within the structure impart hydrophilic and lipophilic features to the surfactant. Nonionic surfactants do not have a net charge. Nonionic surfactants are usually products of a petrochemical process. Consequently, the nonionic surfactants tend to be expensive and to have limited environmental compatibility.
Surfactants interact with herbicides in a number of ways both before and after application to a crop. In addition to having use as an emulsifier, a surfactant may act as a penetrant, spreader, sticker, stabilizer, wetting agent, dispersant and defoamer. The surfactant may affect a rate of drying of a droplet on a plant and the nature of a residue, liquid or crystal. The surfactant may influence the weathering characteristics of the herbicide, including rewetting characteristics.
Surfactants have not typically had an effect on odor of herbicides when blended with herbicides. An unpleasant odor emitted by many herbicides has tended to restrict the use of these herbicides. For instance, a herbicide, 2,4-dichlorophenoxy acetic acid (2,4-D), has use in killing broadleaf weeds. Unfortunately, 2,4-D emits an unpleasant odor. The odor discourages use of 2,4-D in suburban areas.